When medical treatment is paid for by society, society will decide who gets treatment. In the future someone, possibly the doctor, will decide if treatment will continue. More than likely it will be a medical database of probable statistical outcomes. If the numbers are against you, you're toast.

Cost benefit analyst will rule the day.

This will cover everyone, not just children.

Religious beliefs will all be cast aside. It will not be a consideration.

We are closer to this than you may realize. It doesn't matter if you agree or not. The reality is that we cannot dedicate resources to keeping the elderly alive just because. There has to be a reason for us to fix you. What's in it for society? Are you going back to work and will pay taxes to pay back society for it's cost of saving you? Are you a scientist working on new inventions that make life better for the living?

The future of medical development will be focused on expanding human capability while in the prime of life including expanding the productive years, not extending unproductive years. Social Security and Medicare cannot be sustained now. We need to make the smaller working class more productive longer.

These sound like harsh decisions, but they will need to be made. The responsibility for taking the child off life support will be the "system". The "system" will be unbiased, cold, and calculating.

We will give new meaning to "You're number is up".
Doctor to the parents, "The numbers look bad".
This will be the new euthemism for "We're going to let your child die".

The old gods are dead, let's invent some new ones before something really bad happens.

If a parent retains hope regardless of the reason for that hope then the doctor's primary responsibility is to present whatever facts are available. Any parent will need to go through a grieving process before they can accept those facts to the point where they are prepared to act on them.

If at all possible at any time the decision to terminate medical treatment should be made with parents, not in spite of parents. Only in the most extreme cases could I back a call for the parent's role to be bypassed, and those cases should be justified both by the cost of continued treatment and more specifically by the loss of availability of medical care to other patients.

Give me your argument in the form of a published paper, and then we can start to talk.